Printing apparatuses which print an image to be printed on a printing medium as the printing apparatuses move across the printing medium are known.
For example, Unexamined Japanese Patent Application Kokai Publication No. 2008-094101 discloses a handheld printer that detects the moving amount of a printing apparatus on a printing medium by means of an optical sensor, and discharges an ink according to the moving amount of the printing apparatus, which is detected by the optical sensor, thereby printing an image on the printing medium.
There are types of printing media on which an optical sensor may not accurately detect the moving amount of a printing apparatus easily. When the handheld printer described in the above-mentioned literature is used to print an image on such a printing medium, the printing may not be appropriately made because the optical sensor may not accurately detect the moving amount, and the printing quality is degraded.
In view of the above, it is desired to restrain degrading of printing quality by enabling appropriate printing even on such a printing medium on which an optical sensor may not accurately detect the moving amount of a printing apparatus easily.